1. Field of the Invention
The invention relates to an underground container, which is intended to accommodate electronic subassemblies.
2. Description of the Prior Art
In currently available copper telephone networks, a cable branching point (CBP) is connected between the trunk cable area and the subscribers. The trunk cable area extends between the CBP and the exchange over several kilometers, whereas the branching area is restricted to a length of less than 1000 meters, on average this is about 300 meters. Over this distance it is also possible to transmit messages at considerably higher bit rates.
If it is intended to open up new services for the subscriber, the short lines in the branch area have the advantage that only the trunk cable area has to be re-equipped for higher data rates.
Since the trunk cable is mostly laid in pipes or cable ducts, it is possible, for example, for a new optical fiber cable, which, for example, replaces the previous trunk cable, to be laid without great effort. The subscribers are supplied with the new services following appropriate conversion of the signals transmitted via optical fibers into electrical signals. The fact that a change in the branch area is not necessary is particularly important because the branch cables have mostly been laid as underground cables and would be replaced by optical fiber underground cables only at considerable cost.
However, since additional electronic subassemblies are necessary for the conversion of optical signals into electrical signals, more space is required for these active components. The problem lies in their accommodation. Only seldom is it possible to arrange a further housing alongside an existing CBP. Therefore, underground containers to accommodate additional electronic subassemblies are provided as additional housings. During the installation of new networks, above-ground cable branching points can be dispensed with, by all the subassemblies being arranged in underground containers.
The problems in the case of the underground containers reside in the sealing of the housing, including the cable lead-throughs, the dissipation of heat (if active components are accommodated), the protection of the components during mounting work and the mechanical strength with respect to vehicles rolling over the said containers.